1. Technical Field
The present invention relates to a functional liquid tank for receiving the supply of functional liquid from a functional liquid supply source and supplying the functional liquid to an inkjet functional liquid droplet discharge head. The present invention also relates to a method for replenishing functional liquid in a droplet discharge device and to a droplet discharge device.
2. Related Art
In conventional practice, there has been known a method for filling a droplet discharge head with functional liquid. According to this method, the functional liquid is not replenished in a droplet discharge device, but the flow channels in the head of a droplet discharge head are filled with functional liquid by feeding and suctioning (see Japanese Laid-Open Patent Application No. 2004-188410). This functional liquid filling method is implemented primarily when the droplet discharge head is replaced, and the method comprises a pressurizing liquid feed step in which compressed air is supplied to an airtight liquid supply sub-tank, the functional liquid in the liquid supply sub-tank is fed to the droplet discharge head, and the functional liquid fills the flow channels in the head of the droplet discharge head; and a suction step following the pressurizing liquid feed step, in which a suction unit is driven and functional liquid is suctioned from the nozzles of the droplet discharge head. Thus, the droplet discharge head is subjected to a filling action for feeding the functional liquid and a subsequent functional liquid suctioning action, thereby making an initial filling possible and preventing air bubbles from remaining in the flow channels in the head.